Being filmed during wartime, Alfred Hitchcock’s call-to-arms was, by necessity, almost totally studio-bound, filming at the independently-owned studios of Samuel Goldwyn.

It's claimed that almost 100 sets were built, ranging from a square in ‘Amsterdam’ (needing a diversion of a river and a sewer system to provide the rainstorm); an 80-feet, three-tiered windmill; the cabin of a crashing plane (which alone cost $160,000 and was suspended on wires to plunge into the studio tank) to a gigantic mock up of London’s ‘Waterloo Station’.

One real London location was captured by a second unit to be edited into the studio production. Cuddly – but lethal – retired assassin Rowley (Edmund Gwenn) plummets from the campanile of Westminster Cathedral, Victoria Street, Victoria.

Despite the plaza in front of it, the exotically Byzantine Catholic cathedral still feels hemmed in by shops and office blocks. The darkly glittering interior still unfinished, though it does contain Stations of the Cross sculpted by the sexually rapacious Eric Gill (who was also responsible for the scandalous carving of Prospero and Ariel adorning the BBC’s Broadcasting House in Portland Place).

The exotically European interior was exploited by director Shekhar Kapur for Elizabeth: The Golden Age, where it doubled for the Escorial, the Spanish palace of King Philip II of Spain. In 1978, the red-and-white striped exterior of brick and Portland stone became (on the outside, at least) a decadent disco run by Borgia Ginz in Derek Jarman’s punk nightmare Jubilee.

You can take the lift up to the top of the belltower if you want to see an endless vista of ugly rooftops (admission charge).